Maize is one of the most important cereals crop broadly adapted to different agro-ecologies worldwide. The experiment was conducted with the objective to evaluation of open pollinated maize varieties for the adaptability and stability of grain yield and yield related traits for mid altitude areas of Western Guji Zone. Different genotypes have different performance in each region that can be capitalized to maximize productivity. Six open pollinated maize varieties were brought from Bako National Maize Research Center and planted in RCBD with three replications at Galana and Abaya sub site of Yabello Pastoral and Dryland Agriculture Research Center for three respective years. Analysis of variance showed that, significant yield difference was recorded among genotypes. The combined analysis of variance indicated that highest average grain yield of 5.85 t/ha was obtained from Gibe-2 followed by 5.63 t/ha for Kulani variety across years and locations. Stability analysis revealed Kulani was the most stable variety among all while Gibe 2 was unstable. The Additive main and multiplicative interaction stability value (ASV) of Kulani and ABO-Bako were close to zero (0.08 and 0.27, respectively), while the ASV of Gibe 2 was relatively higher (1.62) deviating from zero. Therefore, Kulani was stable and high yielder across environments while Gibe 2 was high yielder in specific environment (unstable). So, and Kulani had been promoted for cultivation in Galana and Abaya districts of southern Oromia and areas with similar agro ecologies, while Gibe 2 was recommended for Galana district.

Keywords: Adaptation, ASV, Genotypes, Stability, Zea mays